"Now we have got a whole new set of challenges," Coach Lane Kiffin said Sunday during a teleconference with reporters.

Arizona, AP No. 2 Oregon, Arizona State and UCLA all rank among the top 25 offenses nationally. Fifth-ranked Notre Dame is second in scoring defense and sixth in total defense.

On Saturday, USC will play at Tucson, where an Arizona team coming off a 52-17 victory over Washington awaits.

Arizona, under first-year Coach Rich Rodriguez, is 4-3 overall and 1-3 in the Pac-12 Conference. But the Wildcats boast an offense that has averaged 549 yards a game, which ranks fifth nationally. Arizona has averaged 39 points.

"They run a million snaps a game at a really high tempo," Kiffin said. "And there's going to be some heat involved."

Penalty problems

USC remains the nation's most penalized team, averaging 9.9 a game.

Kiffin described the Trojans' first half against Colorado as "a disgrace" and said, "I'm hoping that we hit rock bottom."

Kiffin said the coaching staff spent all of halftime focused on penalties and maintaining composure on the field.

"I don't know if they've ever been talked to like that," he said, adding that team leaders "for the first time" have taken "ownership" of the issue.

"We need to play more disciplined," Woods said after Saturday's victory. "The past couple of weeks we've had a lot of personal fouls."

USC anticipates that the Pac-12 will decide Monday what discipline, if any, freshman defensive tackle Leonard Williams will face after being ejected for a flagrant foul. Trojans players said Williams was spat on by a Colorado player before the incident.

Numbers game

USC special-teams coach John Baxter is known for having specialists change numbers to confuse opponents.

The official play by play of the Colorado game says quarterback Cody Kessler tried a two-point conversion run in the first quarter that was nullified by a penalty.

But that sure looked like punter Kyle Negrete.

Asked whether Negrete had replaced Kessler as the holder for place kicks, Kiffin said, "I'd really rather not get into that at this time for certain reasons."

Receiver Marqise Lee also tried a two-point conversion run out of the wildcat formation.

Although the plays failed, they achieved their aim of giving future opponents something to think about.

"That's a huge part of it," Kiffin said. "That's why we do a lot of the stuff we do.

"It's a pain to prepare for. You've got to waste time preparing for that instead of spending time on offense and defense. Marqise in the wildcat; now you've got to have a plan for that."

Quick hits

Offensive tackle Aundrey Walker, who was carted off the field Saturday because of an unspecified injury, attended team meetings Sunday and "things seem to be very positive," Kiffin said…. Senior defensive end Devon Kennard, who underwent surgery for a pectoral injury on the eve of training camp, will not play this season and will redshirt, Kiffin said. Senior cornerback Brian Baucham, who returned to classes last week after being hospitalized for head and breathing issues after the California game, will not play again this season. Defensive lineman Cody Temple had ankle surgery and also is out for the season, Kiffin said.